[SeeSharp]

One US test was a "dud". A few Russian efforts are believed to have been in some early cases publicity stunts that probably failed

I think Britain faked one of their tests also.

[FredZarguna]

I think Britain faked one of their tests also

Wouldn't surprise me. It was a prestige club, and people forget how hot the Cold War was at some points in the late forties/early fifties -- a lot of history ignoramuses think the Cuban Missile Crisis was the only "near thing."

The NoKoreans had a very low yield in the one test we actually have confirmed and that wasn't even an H-Bomb. Some analysts thought it might actually be a conventional high explosive test it was so feeble. I believe that probably means it was Plutonium.

[parsifal]

I think I read a book about this once. The Jesus Factor?

parsy, whose memory is going downhill